DIY Magnetic Double Glazing

Imagine turning your existing single glazed windows into double glazing with 80-90% of the benefit and 10% of the price of new double glazed windows. Yes, Frugal Man has outdone himself this time. Hold on to your hats, it is even EASY! I know, I know, if I could clone that man, I’d make a zillion dollars.

Since cloning Frugal Man is out of the question, y’all will have to settle with the knowing how to make your own magnetic double glazed windows. Yes, it is disappointing, but you’ll just have to live with it as best you can.

You’ll need adhesive magnetic strips (we got ours on TradeMe, similar to eBay), 3mm (1/8 inch) polycarbonate sheets (from our local glass shop) cut just short of the size of your window panes to allow for thermal expansion and, if you have wooden windows, some wooden stripping about 12 mm (1/2 inch) square. You can use acrylic (aka Perspex, Plexiglass, Lucite etc) but polycarbonate (aka Lexan) is extremely tough and shatter resistant.
The distance between the existing pane and the plastic sheet should broadly be around 12mm (1/2 inch) to 25mm (1 inch), with the thickness of the two magnet strips plus the wood strip spacer, we have about a 3/4 inch gap. This is a good spacing for thermal insulation, for acoustic insulation about 4 times the gap is optimal.

First, inspect the window you want to double glaze and determine if it is a wooden or aluminum frame. The kitchen window we did this weekend was wooden, but we are doing the rest of the windows, which are aluminum soon. I’ll give you the instructions for wooden windows now and then document the aluminum windows with pics when we do those.

For wooden windows, you will need to get wooden stripping, about 12 mm (1/2 inch) square and cut pieces to frame the inside of the windows you wish to glaze. In the picture, you can see the framing that Frugal Man has done for each window pane. Each piece of the frame needs to be cut precisely and screwed into the side of the window. These mini-frames give your magnetic strips somewhere to sit.

To drill into the window frame you probably won’t be able to use an electric drill because the glass will stop you getting the correct angle for the hole. We cut the pieces to length then drilled and countersunk the holes in the wood strips before placing them in the window frame and using them as a guide to drill the frame holes with a small hand drill.

Once any required frames are attached, clean, dry and check the polycarbonate sheeting for a good fit in the window. Stick the magnetic strip all around the edge of one surface of the sheet.

Before you go any further note that the rolls of magnets come in A and B variants. One you place on the plastic directly and the other ends up on the frame. The magnets we used were visually identical and were not marked as different in any way. We did notice that A will stick to A, but it sticks with an offset of several millimeters. Before cutting the magnets, check that they do actually line up naturally with no offset.

Next, cut more magnet strips for the window frame. The easiest way to precisely apply these is to put these in place on top of the magnets that you have adhered to the polycarbonate, adhesive strip side up, and then when you are ready to put the pane in place peel the adhesive backing off the strip and then stick the entire thing into the window so that it adheres to the wooden strips.

Once it is firmly adhered, use a knife or screwdriver to remove the polycarbonate sheet and top magnet strip, leaving only the bottom magnet strip and mini-frame. Press firmly on any bits of magnet that need re-adhering both on the polycarbonate sheet and on the mini-frame. Allow both sets of magnet to sit for a few minutes before returning the polycarbonate sheet to the mini-frame.

Congrats, you’ve double-glazed a window pane! Repeat for any other window panes you wish to double glaze. Bask in the improved insulation plus the reduced sound spillover from your neighbor’s dreadful musical taste.

Special thanks to Frugal Man for his help in writing this post today, my eyes were starting to glaze over. (Ba-dum-ching!)

Hi we have done this for all our windows in the upstairs of our home, it has worked great for approx four weeks. In the last week we have had 3 warm sunny norwest days (chch) and the magnetic strips have been peeling off the window frames? really disappointing as one of the windows fell out down onto the ground luckily no one was there but it has been scratched. Any ideas why this may have happened?? any suggestions how to remedy situation. As now the strips don’t seem as sticky and they pulled paint off the frames as they pulled away??

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Frugal Man
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August 5, 2014

I presume you have old painted wood around the windows. If the condition of that wood isn’t great or the paint isn’t well adhered or the surface just isn’t smooth or it’s dirty then that’s going to be a problem. If the sticky isn’t sticky anymore then I suspect whatever was on top of the paint is now on top of the magnet adhesive. To solve this problem I think there are really two options – either refinish the wood so that the surface is better, or provide a secondary adhesion surface (such as a thin flat strip of aluminium screwed onto the frame the the magnet could then stick to).

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Sujay
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December 15, 2012

Re:
“I made something similar using velcro for all our opening windows. I made fly screen. Different season I know but we were quoted 2500$ for flyscreens, I made them for 300$. Easy as and no more little people or me getting mozzie bites in the night”

We did something similar using velcro (bulk rolls is cheapest) and bridal tolle material (fine mesh used for bridal veils etc). Lot of variation in price, texture and size of tolle, but possible to find low cost material off the roll at fabric shops.

The mesh of tolle is fine enough to exclude sandflies. (much finer than most flyscreen mesh) hoosing the right colour makes the tolle mesh almost invisible.

Cost was ultra low and lasts at least a couple of years. Ideal for rented housing. Had to sew in small fabric triangles on the corners to reinforce the fine mesh from tearing.

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Dave
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October 22, 2012

I have double glazed our timber frame windows using perspex and A/B magnetic tape and would recommend it for heat insulation. However the windows that have sun on them get condensation between the glass and perspex. I have tried heating up the air just before sealing the magnets, I have put tape around the edges of the perspex and onto the timber frame just in case the magnets arent sealing properly. I had a humidity meter put inside to gap and it read 33% to start with then with sun it shot up to 55% inside the gap. I have tried to seal up all gaps and still condensation. Non sunny windows dont have anycondesation. Do you know whats going on as the condensation is bad

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Frugal Man
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October 22, 2012

If the seal isn’t airtight and the volume of trapped air is reasonably large then as the air heats/cools it will circulate the air in and out as it expands and contracts. The sunny windows would be worse for this as they will go through greater heating and cooling cycles. So that will draw moisture in with the air at night. If you can minimise the size of the gap to a couple of mm or so it may help this.

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Dave
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October 22, 2012

the air gap is 28mm due to beveled timber frame and cant be reduced. I realise that there must be an air leakage somewhere but where? I sealed around the newly painted window (A) magnet by applying thick paint to its edges, heated the window with a hot air gun (humidity reading 30%), placed the perspex and (B) magnet onto the window and then masking taped around the edges. Cant do much more than that but next day, with sun, condensation and humidity up to 55% . I see some suggest drilling a hole in the window frame to the outside thus allowing the outside air into the gap, would this work, sounds plausable.

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MariH
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July 8, 2012

Bryce, I tried the adhesive foam double sided tape and it did not cope with the heat or cold , which caused it to peel off , after just a few days. I then changed to double sided clear sellotape and it coped fine for 2 winters and summer, and was still fine when I moved out after 18 mths of it being there. The sellotape was only about 8mm wide compared to the 20mm of the other tape so was less conspicuous too.

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MariH
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July 9, 2012

Hi Bryce, Why is it when u know u have something and look for it, it has moved?? It was just a double sided clear sticky tape a bit under 1cm wide. I think it was sellotape or cellotape or 3M or something similar. It was nothing special, would be in any craft or hardware store. I brought some from a hardware store then found my supermarket had it cheaper. The roll is about 10cm diameter and had I think 10m on it and is clear with a peel off tape on one side. Hope that helps.

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I’ve only just caught up with this after bubble wrapping two of my son’s bedroom windows 2 days ago! Bubble wrap is working a treat but I love the idea of the magnetic strip and being able to see out the window – fantastic, thanks for sharing Melanie & Frugal Man 🙂

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@The Wiser Way You could certainly try it, but it might be that the Velcro backing comes off of the polycarbonate when/if you try to take them off for any reason. We don’t have that problem with magnets.

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MariH
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July 3, 2012

@FrugalKiwi @The Wiser Way Velcro doesn’t give the close seal that magnetic strip or double sided tape does. I did my windows last year where I used to live. They were wooden framed and I used double sided cellotape to hold the plastic on to the outside frame. I used a greenhouse grade plastic that was reasonably thick and it was slightly translucent so gave a modicum of privacy too. When it was on, we used the hairdryer to heat the plastic and tighten it. It worked wonderfully well and stopped the drafts completely and was cheap to do. Add thermodrape drapes and it was really warm, plus cooler in summer too.

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[…] tips to share?While we found bubble wrap insulation worked great, we’ve now created our own DIY Magnetic Double Glazing for a more permanent, but still cost effective, window insulation solution.Related Posts:Energy […]

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DIY girl
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March 5, 2012

Hi, I love this idea and definatly want to give it ago. Could u recommend a trademe user to get the magnetic tape from? I’m a bit unsure as to which type. I use some for making magnetic kids stories and invites but not sure if it’s the same strength

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Frugal Man
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November 15, 2011

Note that in many cases you don’t need a subframe, you could just put the magnets on the existing frame. In our case the frame wasn’t really suitable for that approach, so we used a subframe and effectively made the windows a little smaller. Your windows may vary.

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Brilliant idea, a great way to save extra money for those people who want to be energy efficient and keep their own homes warn but just don’t have the funds available. Replacing whole window systems can be remarkably expensive and often a lot of hassle.

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frugal man
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October 31, 2011

I doubt it makes any difference, it’s mainly about the size of the air gap. I went for polycarb because it is virtually indestructible where acrylic is more likely to crack, but mechanically the behaviour of the two seem quite similar in terms of density and flexibility. I guess that thicker is better too if the neighbour’s parties are driving you nuts.

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[…] effort trying to save energy by using super simple BubbleWrap Window Insulation and more permanent DIY Magnetic Double Glazing. More impressive savings-wise was our switch from a standard fridge-freezer that was costing us […]

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Hope it works for you too. Whilst we were in Auckland yesterday, we picked up enough magnetic strips to finish off the rest of the windows in the house from the TradeMe guy and save ourselves the shipping. Obviously we are sold on the scheme!

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Helen
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July 8, 2011

Hi Mel,
I made something similar using velcro for all our opening windows. I made fly screen. Different season I know but we were quoted 2500$ for flyscreens, I made them for 300$. Easy as and no more little people or me getting mozzie bites in the night!

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Frugal Man
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July 7, 2011

A few extra points about this project …
* Single glazed windows can amount to half your heat energy loss
* Thermal drapes are only really worthwhile if they hold the cold air around the window and don’t let it spill out over the floor (so they need to go onto the floor)
* Clean plastic with non-alcohol cleaners

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Sophie
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July 7, 2011

I very like this!!!

Our windows come in several odd shapes – the cost for curtains would be ridiculous, let alone replacing them with “true” double glazing. Personally I’m tempted to get a builder to knock them into more standard shapes…

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So if you’re already doing the bubble wrap insulation would this then eliminate the need to do that? I’m also curious about prices–obviously cheaper than replacing windows but can you give some ballpark figures?

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You could do this double glazing then put the bubblewrap on top if you were so inclined. We are inclined to skip the bubblewrap now we have double glazing.

Prices here in NZ will vary HUGELY from prices in the US, but it cost us $45 for the magnetic strips, $10 for the wood, and about $125 for the polycarbonate, so $180 all up. New double glazed windows would be $2,000-$3,000. This is for a window that is more than 6 foot tall and 3 plus foot wide. I’d expect you to be able to get materials in the US for half what we paid or even less.